It has been known that oil-and-fat based food materials such as chocolate, baked confectionery, snack, fried confectionery, candy, filling, nut paste can be used as a composite confectionery alone or in combination. Especially, a chocolate composite confectionery in which chocolate is combined is popular item.
A chocolate composite confectionery includes various forms. For example, so called “shell chocolate” has a form that a part called as “shell part” covers the outside of a part called as “center part” as core. Typically, an oil-and-fat which is relatively-soft at room temperature (i.e. an oil-and-fat including relatively-high level of liquid oil component) is used as a raw material of a food material for the center part in order to provide softness, good meltability in the mouth and texture different from that of the shell part.
In addition, the other variations of chocolate composite confectionery includes: a confectionery in which chocolate and nut are combined by filling fried or roasted nuts into chocolate or by coating nut with chocolate (hereinafter referred to as nut chocolate); and a confectionery in which chocolate and baked confectionery, which includes flour as main ingredient and is produced by frying or baking, such as biscuit and pretzel, are combined (hereinafter referred to as baked goods-combined chocolate).
In the shell chocolate, usually, soft oil-and-fat at room temperature is used as a raw material of a filling part of the center while hard oil-and-fat at room temperature (i.e. oil-and-fat including relatively-low level of liquid oil component), such as cocoa butter and cocoa butter alternative, is used as a raw material of the shell part. Thus, a content of liquid oil component of both parts are different.
In addition, in the nut chocolate, nut includes high level of fat-and-oil which is relatively-soft at room temperature while chocolate part includes fat-and-oil which is relatively-hard at room temperature as a raw material. Further, in the baked goods-combined chocolate, baked confectionery includes high amount of fat-and-oil which is relatively-soft at room temperature, such as margarine for kneading and oil-and-fat for spraying, while chocolate part includes fat-and-oil which is relatively-hard at room temperature as a raw material similar to the nut chocolate. Moreover, both nut and baked confectionery become to include higher amount of liquid oil when treatment such as frying is applied.
This difference of the amount of liquid oil component between the oil-and-fat based food materials causes a migration of the liquid oil from a high content part to a low content part. In the case of shell chocolate, it has been a problem that a commercial value of the shell chocolate is significantly lost by softening the shell part or whitening the surface (blooming) due to the oil-and-fat migration from the center part to the shell part.
The following three means for solving such an oil-and-fat migration are well known for a long time:
1. Increasing hardness and melting point by adding hard oil-and-fat having about 32 to 38° C. of melting point, such as cocoa butter and cocoa butter alternative, to center cream;
2. Using a fat stabilizer system (adding a small amount of high melting point oil-and-fat having 40 to 70° C. of melting point to center cream in order to make solid grid-like formation);
3. Blocking an oil-and-fat migration by coating an interface between center cream and chocolate with sugar, protein, polysaccharide film sugar etc. (Non-Patent Document 1).
Although the above means 1 can effectively reduce the oil-and-fat migration, original softness and creaminess of center cream is deteriorated and it is hard to exude flavor.
In addition, the above means 2 can reduce a cost because an effect can be obtained by adding a small amount of high melting point oil-and-fat. However, flavor of the center cream tends to be remarkably deteriorated and texture of the center cream tends to be waxy and bad in the mouth.
The last, the above means 3 seems to significantly effective. However, it is not practicable due to problems such as uncomfortable texture and complication of coating.
As a recent technology, a fats and oils composition comprising: (A) fats and oils comprising 50% or more of palm oil, and (B) fatty acid polyglycerin ester of 0.05 to 5% by weight or more, wherein the constituent fatty acid comprises oleic acid and palmitic acid of not less than 80% by weight based on the weight of constituent fatty acid, and the molar ratio of said oleic acid to said palmitic acid is 90:10 to 10:90, is proposed (Patent Document 1). However, nothing is suggested for a bloom and a softening of shell chocolate that appear when food materials having a different content of liquid oil component are combined.
Another, for a shell chocolate, an oil-and-fat composition for center cream comprising 0.1 to 0.2 wt % of lipophilic emulsifier and 0.2 wt % or less of lecithin is proposed (Patent Document 2).
For a nut chocolate, a method for preventing oil-and-fat migration by making an oil-and-fat composition of chocolate part to comprise 50 wt % or more of 2-oleo-disaturated triglyceride (SUS), 0.5 wt % or more of 2-oleo-palmito-arachidine (POA), 2 wt % or less of tri-saturated triglyceride (S3) and 0.01 wt % or more of triglyceride containing dihydroxy fatty acid (DHTG) is proposed (Patent Document 3).
For a combination of baked confectionery or nut, and oil-and-fat for chocolate, cream and spraying, a method of using an oil-and-fat composition for composite confectionery, comprising a lipophilic polyglycerol fatty acid ester and (or) a lipophilic sucrose fatty acid ester, wherein two or more of fatty acids constituting the polyglycerol fatty acid ester and the sucrose fatty acid ester are saturated fatty acid having 18 or more of carbon atoms, and wherein SFC value of the fats and oils is 20 or more at 20° C., 7 or more at 30° C. and 5 or less at 40° C. is proposed (Patent Document 4).
However, although any methods use a method of adjusting solid fat content for reducing the difference of contents of liquid oil component, or a method of cutting a crystal of oil-and-fat by adding a lipophilic polyglycerol fatty acid ester and/or a lipophilic sucrose fatty acid ester, no strategies for addressing a bloom due to an oil-and-fat migration are shown.
In addition, these inventions are the examination of the material combined with chocolate, material on the side of higher amount of liquid oil component. No solutions for the side of chocolate to which liquid oil migrates are disclosed.
Further, as an oil-and-fat composition for chocolate, a hard butter composition comprising 6 to 12% of total amount of StOO and POO components, 25% or less of POSt component and having 40 or less of iodine value, 23° C. or more of a minimum temperature and 27.5° C. or more of a maximum temperature in a cooling curve determined by Jensen method (Patent Document 5), and an oil-and-fat composition comprising lipophilic emulsifier having an effect of delaying crystallization (Patent Document 6) are proposed.
However, the effect of solving the problem due to an oil-and-fat migration by the above-mentioned prior art is considered to be insufficient in recent years. It is because to coat chocolate to baked confectionery more thinly and a combination with a chocolate including higher amount of milk powder tend to be preferred in recent years, and such confectionery tends to show oil-and-fat migration and following low temperature bloom and softening of chocolate more significantly.
Therefore, there has been a strong demand from the market for a technology for preventing an oil-and-fat migration and following bloom and softening of chocolate.